A lot of probiotics that you buy contain multiple strains of bacteria, but water kefir kicks butt on all of them. Some studies show in excess of 450 strains from water kefir!! These bacteria and yeast can provide huge relief from gut issues, brain fog, fatigue, and are anti-inflammatory, anti-tumour, anti-fungal, anti-bacterial, and can improve lactose digestion in those that are intolerant. So easy to make, and only costs a $1 per liter.